Added test step that changes to a safe directory for testing files to be created, runs the unit tests for assimp, and verifies they ran without error

Signed-off-by: AMZN-stankowi <[email protected]>

package-system/assimp/test_assimp_windows.cmd

@@ -3,4 +3,22 @@
 @rem # For complete copyright and license terms please see the LICENSE at the root of this distribution.
 @rem # 
 @rem # SPDX-License-Identifier: Apache-2.0 OR MIT
-@rem #
+@rem #
+
+set curdir=%cd%
+
+rem The tests leave behind a lot of temp files in the current working directory,
+rem so change to a directory in temp to keep things clean
+cd temp
+mkdir test_out
+cd test_out
+
+%TARGET_INSTALL_ROOT%\bin\Debug\unit.exe || goto ExitWithError
+%TARGET_INSTALL_ROOT%\bin\Release\unit.exe || goto ExitWithError
+
+cd %curdir%
+exit /b 0
+
+:ExitWithError
+cd %curdir%
+exit /b 1